MathCastle
Number TheoryChallengeFactors & Multiples

Factors & Multiples · Challenge problem

Lighthouse A flashes at times 0,9,18,27,…0, 9, 18, 27, \ldots seconds and lighthouse B at times 2,16,30,44,…2, 16, 30, 44, \ldots seconds. At what time does A first flash exactly 11 second after a flash of B?